make config path distribution-dependent
make config path distribution-dependent

this fixes a configuration error on the FreeBSD platform
where is the 3rd-party software configuration placed
has a prefix /usr/local.

Tested on: FreeBSD 12.0-RELEASE, FreeBSD-13-HEAD

voxpupuli/puppet-rabbitmq,puppetlabs/puppetlabs-rabbitmq,Slm0n87/puppet-rabbitmq,Slm0n87/puppet-rabbitmq,Slm0n87/puppet-rabbitmq,puppetlabs/puppetlabs-rabbitmq,voxpupuli/puppet-rabbitmq